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fix(security): harden XMLUtils against XXE (PR1/9) #36354

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fix(security): harden XMLUtils against XXE (PR1/9) #36354

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25 changes: 24 additions & 1 deletion dotCMS/src/main/java/com/dotmarketing/util/XMLUtils.java
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Original file line number Diff line number Diff line change
Expand Up @@ -6,6 +6,7 @@

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import java.io.BufferedReader;
import java.io.ByteArrayInputStream;
import java.io.File;
Expand All @@ -18,7 +19,29 @@

public class XMLUtils {

private static final DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
private static final DocumentBuilderFactory factory = newSecureDocumentBuilderFactory();

/**
* Builds a {@link DocumentBuilderFactory} hardened against XML External Entity (XXE)
* attacks (CWE-611). The primary defense disables DOCTYPE declarations entirely; the
* remaining features are defense-in-depth in case a future caller re-enables DOCTYPEs.
*/
private static DocumentBuilderFactory newSecureDocumentBuilderFactory() {
final DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
try {
// Primary defense: completely disable DOCTYPE declarations.
dbf.setFeature("http://apache.org/xml/features/disallow-doctype-decl", true);
// Defense-in-depth: do not resolve external entities or external DTDs.
dbf.setFeature("http://xml.org/sax/features/external-general-entities", false);
dbf.setFeature("http://xml.org/sax/features/external-parameter-entities", false);
dbf.setFeature("http://apache.org/xml/features/nonvalidating/load-external-dtd", false);
dbf.setXIncludeAware(false);
dbf.setExpandEntityReferences(false);
} catch (final ParserConfigurationException e) {
throw new DotRuntimeException("Unable to configure a secure XML parser", e);
}
return dbf;
}

/**
* This will take the three pre-defined entities in XML 1.0 (used
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